You can get now all unconfirmed transactions by address, here is the endpoint:

https://docs.cryptoapis.io/rest-apis/blockchain-as-a-service-apis/btc/index#btc-address-unconfirmed-transactions-endpoint

In case you need the confirmed transactions by address, here is the already existing endpoint:

https://docs.cryptoapis.io/rest-apis/blockchain-as-a-service-apis/btc/index#btc-address-transactions-endpoint